hellcat is more likely just hell + cat, possibly suggested by Hecate, the Greek goddess of witchcraft and stuff.

Shakespeare used hellkite (lit. a kite from hell) in Macbeth: "All my pretty ones?..Oh *Hell-Kite! All? What, All my pretty Chickens?" a person of hellish cruelty?

coincidence? well, hellcat and hell-kite found print in the same year! (1605)